AVO技术在煤层气勘探中的应用
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摘要
现有研究成果表明,煤层气含气性和密度间存在负相关关系,煤储层的含气量与纵波速度、横波速度的变化密切相关。在达到AVO技术对地震资料的品质要求下,这种关系则可以通过AVO异常反演直观的体现出来。研究区韩试12井与合试5井的11#煤层正演模拟结果表明,韩试12井11#煤的AVO响应特征为反射振幅随偏移距增大而减小,其煤层顶板为负截距、正梯度,底板为正截距、负梯度,表现为典型的煤层气富集特征;而合试5井11#煤则无AVO异常响应,表现为低含气量,该解释结果与排采数据较吻合。韩试12井AVO的反演结果证明,依据截距、梯度数据体运算获得的AVO异常综合剖面图,可有效预测煤层气富集有利区域及部署煤层气高产井井位。
According to research findings available,the CBM gas bearing property is negatively correlated with density,and coal reservoir gas content is closely correlated with variation of P wave and S wave velocities.If the AVO technique can meet the demand of seismic data quality,the relationship can be reflected visually through AVO anomaly inversion.The forward simulation results of coal No.11 in Hanshi No.12 and Heshi No.5 wells have shown AVO response characteristics of coal No.11 in Hanshi No.12 well have the reflection amplitude decreasing along with offset increasing,coal roof negative intercept,positive gradient,coal floor positive intercept,negative gradient,thus appear as typical CBM enrichment characteristics;while coal No.11 in Heshi No.5 well has no anomalous response,shown as low gas content,the interpreted results are rather tally with drainage data.Hanshi No.12 well AVO inversion result has proved that the AVO anomaly comprehensive section from intercept,gradient data volume operation,can effectively predict CBM enrichment beneficial region to allocate CBM prolific well sites.
According to research findings available,the CBM gas bearing property is negatively correlated with density,and coal reservoir gas content is closely correlated with variation of P wave and S wave velocities.If the AVO technique can meet the demand of seismic data quality,the relationship can be reflected visually through AVO anomaly inversion.The forward simulation results of coal No.11 in Hanshi No.12 and Heshi No.5 wells have shown AVO response characteristics of coal No.11 in Hanshi No.12 well have the reflection amplitude decreasing along with offset increasing,coal roof negative intercept,positive gradient,coal floor positive intercept,negative gradient,thus appear as typical CBM enrichment characteristics;while coal No.11 in Heshi No.5 well has no anomalous response,shown as low gas content,the interpreted results are rather tally with drainage data.Hanshi No.12 well AVO inversion result has proved that the AVO anomaly comprehensive section from intercept,gradient data volume operation,can effectively predict CBM enrichment beneficial region to allocate CBM prolific well sites.
引文
[1]张兴平.高、低煤层气井AVO正演特征及其识别[J].中国煤炭地质,2011.231061.
[2]师素珍,韩毅,刘万金.含煤地层AVO正演模型参数优选分析[J].中国煤炭地质,2009,21(04).
[3]杜文凤,彭苏萍,王珂,等.瓦斯突出煤和非突出煤AVO响应的比较[J].中国煤炭地质,2010,22(06).
[2]师素珍,韩毅,刘万金.含煤地层AVO正演模型参数优选分析[J].中国煤炭地质,2009,21(04).
[3]杜文凤,彭苏萍,王珂,等.瓦斯突出煤和非突出煤AVO响应的比较[J].中国煤炭地质,2010,22(06).
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